Ketodisiloxanes



Patented Apr. 8, 1952 e UNITED STATES PATENT OrFFI' CE KETODISILOXANES Leo H. Summer, Cambridge, Mass, assignor to- Dow Corning Corporation, Midland,.Mich., a corporation of Michigan No Drawing. Application January 3, 1951,

Serial No. 204,271

6 Claims. (Cl. 260-4482) 1 2 This invention relates to ketodisiloxanes where- The latter compound upon hydrolysis, treatin the oxygen is attached to a carbon atom gamma ment with SOC12, and then R '2Cd as in Equation to the silicon, and to their method of preparation. 1 produces R.(CH3) 2SiCH2CHR'COR. These re- It is an object of this invention to prepare novel actions are described in greater detail by Leo H. siloxanes which are excellent solvents, are inter- 5 Sommer and Nelson S. Marans Journal of the mediates for the preparation of other siloxanes, American Chemical Society 72, page 1935, May

and are additives for siloxane fluids. 1950.

This invention relates to compounds of the The ketosiloxanes of this invention are useful formula [R"COCHR'CHzSi(CHz)2120' where R as solvents, intermediates, and additives for conis alkyl or monocyclic aryl hydrocarbon and R is ventional siloxanes.

hydrogen or alkyl, The following examples are illustrative only These ketosiloxanes are prepared by the suland are not to be construed as limiting the infuric acid cleavage of gamma ketosilanes of the vention, which is defined in the app l formula wcocnacrnsncrnna in which R is Emmpze 1 methyl or phenyl. The reaction is carried out by mixing the acid and the silane, whereupon cleav- 17 grams of 4-t11methY1511y1-2-butan0ne WaS age f t R group occurs with the f mati n f added slowlypwith stirring and external cooling to methane or benzene together with a sulfate ester 9 of concentrated Sulfuric acidl- During addiof the si1ane The latter is then hydrolyzed by tion of the ketone and for 20 minutes thereafter, the addition of water to give a silanol which con- 0 there was evqlution of methane h mix ure denses to the siloxane. The reaction proceeds at was finally surfed d heated for one hour at temperatures of from below 0 0, up P f bly 90 C. The resulting product was poured into an the reaction is carried out between 0 C. and Solutlon 0f 80 grams of H- The C. The reaction may be represented by the mixture was extracted with three 150 cc. portions following hemati equation; of ethyl ether; The combined extracts were dried l over anhydrous sodium sulfate and then fractionated, whereupon 5,5,7,7-tetramethy1-5,7-

H2804 RC OCHRCHzSKCHmR H2O sila-6-oxa-2,10-undecaneione R" o o CHRCHzSi (CH3) 2 0S 03E [*CHg'CO'GHgCHgSi (CH3) sO'Si on3 QCHZ'CHQCOCHSJ R"C0OHR0H2Si CH3)BOH 0 was obtained in 45% yield. This material boiled [R"COCERCH2SKCH3)2]1O at 142 C. at 6 mm., and had a density at 20 C. of 0.943 and a refractive index at 20 C. of 1.4390. The cleavage reaction is quantitative and occurs not only with ketones but also with the corre- Example 2 sponding aldehydes of the formula When (CI-I3)aSiCHzCI-I(CH3)COCH3,

HcocHRcHzsucm) 2R (Cm) 3S1CH2CH(C2H5) COCH3, and (CH3)3SiCH2CH2COCsH5 are treated with The ketosilanes which are employed as inter- Hzsoe as Shown in Example 1, the Co p u s mediates in the process of this invention may be c c0c1-I c )c1-I s H 1 0 prepared by reactin iodosilanes with acetoaceii- [CH3COCH(C2H5) cx-nsucno 2120 and cester and sodium. The equations given below H Co H show the various steps employed to synthesize 6 5 C zcflzsflcmnho these materials. respectively are obtained.

C 1H5 0H Hz 0 R(CH3)zSlCHzI-ICH3COCH:C OzC1H +Na R(CHa)zSlCHzCHzC OgCgH Na in 3% excess That which is claimed is:

1. A method of preparing ketosiloxanes of the formula [R"COCHR'CH2Si(CH3)2]zO where R" is selected from the group consisting of alkyl and monocyclic aryl hydrocarbon radicals and R, is selected from the group consisting of hydrogen and alkyl radicals which comprises reacting a silane of the formula R"COCHR'CH2S1(CH3)2R in which R" and R are as above definedand R is selected from the group consisting of methyl and phenyl radicals with concentrated sulfuric acid to form a sulfate ester of said silane, and thereafter hydrolyzing the sulfate ester to a silanol and condensing the silanol to said ke csiloxane.

4 2. A compound of the formula [R"COCI-IR,'CH2Si (CH3) 2120 where R," is selected from the group consisting of alkyl and monocyclic aryl hydrocarbon radicals and R is selected from the group consisting of hydrogen and alkyl radicals.

3. [CHeCOCHzCHzSHCI-BMHO 5. [CH3COCH(C2H5) CHzSi(CH3) 2120 6. [CsHsCOCHzCI-IzSi (CH3) 2120' LEO H. SOMMER.

No references cited. 

2. A COMPOUND OF THE FORMULA 